Ransom.Locky

Short bio

Ransom.Locky is Malwarebytes’ detection name for the Locky ransomware, which encrypts files on Windows OSes and holds them hostage for ransom. Locky was first discovered at the beginning of 2016 and immediately became one of the most significant malware threats in the wild. As of this writing, Locky is out of commission.

Symptoms

Typically, those infected with Locky ransomware would see a ransom note displayed either as a desktop wallpaper or a text file.

The Locky v1 ransom note, which is displayed to users in two ways: as desktop wallpaper and as a text file. The image file is named _Locky_recover_instructions.bmp, while the text file is named Locky_recover_instructions.txt.

Encrypted files bear the following extension names:

.aesir

.asasin

.diablo6

.locky

.loptr

.odin

.osiris

.shit

.thor

.ykcol

.zepto

.zzzzz

Aside from the presence of the BMP and TXT files mentioned earlier, below are other ransom note files that were found present in Locky-infected systems:

_HELP_instructions.html

asasin-{random characters}.htm

DesktopOSIRIS.htm

diablo6-{random characters}.htm

HELP_Recover_Files_.html

ykcol-{random characters}.htm

Type and source of infection

Ransom.Locky is distributed through the use of both exploit kits (EKs) and malspam. The Neutrino, RIG, and Nuclear EKs have all distributed Locky sporadically in the past.

The Necurs botnet is the main perpetrator behind the malspam that spreads Locky infections, usually as a result of a specially-crafted Microsoft Office Word or Excel file with malicious macros or a ZIP-compressed attachment containing a malicious script.

Aftermath

Systems affected by ransomware are rendered unusable due to files that are typically used for regular operations being encrypted.

Affected users who choose to pay the threat actors behind ransomware campaigns in exchange for access to data may find that they don’t get their files back. There is also no sure way to know that threat actors will honor their end of the deal after paying the ransom.

Affected users who chose to pay the threat actors may also find themselves likely targets for future ransomware campaigns.

Data held hostage that wasn’t given back to users or deleted after the ransom has been paid can be used by threat actors either to (a) sell on the black market or (b) create a profile of the user they can use for fraud.

Protection

Malwarebytes protects users from Ransom.Locky by blocking the malware in real time.

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